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Wang Y.,Institute of Genetic and Developmental Biology | Wang Y.,University of Chinese Academy of Sciences | Hu C.,Institute of Genetic and Developmental Biology | Dong W.,Institute of Genetic and Developmental Biology
Fresenius Environmental Bulletin | Year: 2011

Frequent tillage generally results in soil organic matter loss, microbial activity suppression, and soil structure deterioration. In this study, we have used polymerase chain reaction (PCR) based on 16/18S rRNA sequences, followed by denaturing gradient gel electrophoresis (DGGE) to assess the effect of different tillage managements on soil microbial populations. Soil samples were collected in June 2008 at depths of 0-10 cm and 10-20 cm at Luancheng Agroecosystem Experimental Station, Chinese Academy of Sciences. The three treatments with three replicates were: conventional tillage (CT), rotary tillage (RT) and no-tillage (NT), which represent the typical tillage systems in the North China Plain. Our results suggest that the soil microbial community structure varies under different tillage managements. The community diversities of bacteria were higher in soils under RT and NT than that under the CT in the 0-10 cm layer, whereas there was no significant difference in the community diversity of bacteria within the three treatments in the 10-20 cm layer soil. As for the soil fungi, the community diversities were obviously higher in soils under RT and NT than in the CT in both the 0-10 cm and 10-20 cm layers. These results indicate the sensitivity of soil microbial community to tillage and the necessity of considering the effects of agricultural managements on the soil microbial community when assessing changes in soil microbial community structure and diversity. © by PSP. Source

Changhai S.,Institute of Genetic and Developmental Biology | Changhai S.,Chinese Academy of Sciences | Baodi D.,Institute of Genetic and Developmental Biology | Yunzhou Q.,Institute of Genetic and Developmental Biology | And 5 more authors.
Plant, Soil and Environment | Year: 2010

Pot experiments were conducted to study the variation and physiological regulation of transpiration efficiency (TE) of four winter wheat (Triticum aestivum L.) varieties that are widely grown in different ecological regions in North China. Plants were grown under two soil moisture regimes, normal and drought stress. The results showed that under drought stress condition, both TE at plant level and TE at leaf level (TEI) increased significantly. The transpiration rate (Tr) was reduced more strongly than leaf net CO 2 assimilation rate (Pn). The decline of Tr was mainly affected by stomatal conductance and the decline of Pn was affected by non-stomatal factors, which was confirmed by the decline in net photosynthetic oxygen evolution rate. The leaf soluble sugar content and proline content were significantly increased under drought stress. The stomatal density was increased and the stomatal length was reduced. These results led us to make the following conclusions: (1) Under drought stress, the increase in TEI appears to be regulated in two ways: via the stornata by regulating Tr, and independent of the stornata through regulation of Pn; regulation via the stornata was more sensitive; (2) Osmotic adjustment was closely correlated to the non-stomatal regulation, and stomatal aperture was closely correlated to the stomatal way. Source

Zhai H.,Institute of Genetic and Developmental Biology | Zhai H.,University of Chinese Academy of Sciences | Zhai H.,Shijiazhuang University | Dong B.,Institute of Genetic and Developmental Biology | And 10 more authors.
Fresenius Environmental Bulletin | Year: 2012

In order to diminish environmental stresses of saline water, it is essential to increase soil porosity. One pot experiment with three levels of water salinity (3, 35 and 85 mM NaCl) and two levels of oxygen concentration (Control: about 3.0 mg-L-1; Aeration: 7.0-9.0 mg-L-1) in water was conducted on tomato plants. The results showed that with increased water salinity, plant height, leaf area, biomass and fruit yield were reduced. However, aeration could minimize the impact of salinity, especially at 85 mM water salinity. Leaf water potential was higher under aeration treatment compared to the control. The rates of photosynthesis (Pn) and transpiration (Tr) were elevated by 2.33 umol-m-2-s-1 and 0.69 mmolm -2s-1, respectively, under aeration at 85 mM water salinity, while transpiration efficiency (the ratio of Pn/Tr) was increased by 51.2%. Aeration improved the absorption of K+ and increased the ratio of K+Na+ in the leaf. At 35 mM and 85 mM salinity levels under aeration, the activity of superoxide dismutase in the leaf was up-regulated by 40.8% and 19.2%, the activity of catalase was increased by 38.3% and 61.2%, while the malondialdehyde concentration was reduced by 15.2% and 17.7%, and the electrolyte leakage ratio decreased by 8.9% and 14.7%, respectively. Based on these results, it was concluded that under aeration, the water status and membrane integrity of the plant was improved, with higher antioxidant enzyme activities and greater K+ absorption, which led to a higher salt tolerance, higher Pn and more efficient use of water by the plant. © by PSP. Source

Chen S.,Institute of Genetic and Developmental Biology | Zhang X.,Institute of Genetic and Developmental Biology | Sun H.,Institute of Genetic and Developmental Biology | Ren T.,China Agricultural University | Wang Y.,Institute of Genetic and Developmental Biology
Agricultural Water Management | Year: 2010

A field study was conducted from 2002 to 2007 to investigate the influence of row spacing of winter wheat (Triticum aestivum L.) on soil evaporation (E), evapotranspiration (ET), grain production and water use efficiency (WUE) in the North China Plain. The experiment had four row spacing treatments, 7.5 cm, 15 cm, 22.5 cm, and 30 cm, with plots randomly arranged in four replicates. Soil E was measured by micro-lysimeters in three seasons and ET was calculated from measurements of soil profile water depletion, irrigation, and rainfall. The results showed that E increased with row spacing. Compared with the 30-cm row spacing (average E = 112 mm), the reduction in seasonal E averaged 9 mm, 25 mm, and 26 mm for 22.5 cm, 15 cm, and 7.5 cm row spacings, respectively. Crop transpiration (T) increased as row spacing decreased. The seasonal rainfall interception and seasonal ET were relatively unchanged among the treatments. In three out of five seasons, the four different treatments showed similar grain yield, yield components and WUE. We conclude that for winter wheat production in the North China Plain, narrow row spacing reduced soil evaporation, but had minor improvements on grain production and WUE under irrigated conditions with adequate nutrient levels. © 2009 Elsevier B.V. All rights reserved. Source

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